Typical air grilles incorporate a rectangular metal framework, and a plurality of transverse blades. Usually the blades are rotatable, and are secured by friction, when adjusted, in any particular position. Sometimes two sets of blades are required one behind the other, arranged at right angles to each other.
Manufacturers generally speaking establish a range of sizes or dimensions for such grilles, and are therefore forced to use a variety of components for the frames, and a variety of blades, of differing lengths, to provide different sizes of grilles. Tooling costs and parts inventory can therefore be quite a considerable burden.
However, commercial and industrial requirements for air grilles depend upon architects or engineers specifications, and it is generally speaking not acceptable simply to provide such air grilles in a range of standard sizes. Ideally, the manufacturer should be able to provide air grilles in accordance with any dimensional specifications which the architect requires to suit the particular design of the building under construction. However, such flexibility in dimensions, in accordance with known manufacturing practise, requires either an excessive amount of tooling to produce various sizes of air grilles, or alternatively, involves excessive hand labour and certain manual skills which increase the cost of the air grille significantly.
It is therefore desirable to provide an air grille construction in which the measurements may be entirely flexible and may be varied within wide limits without the use of separate tooling for different sizes, and with a minimum of hand labour such that the cutting, bending and fitting of the various parts as required takes place automatically in accordance with dimensional specifications which have been preprogrammed.